【作者】 赵文峰；

【导师】 李茸；

【作者基本信息】 兰州大学 ， 化学工艺， 2010， 硕士

【摘要】 由于CNT独特的结构、优异的力学性能和光电性能而成为纳米复合材料的理想添加剂,许多科学工作者已对CNTs复合材料的制备及其性能展开了一系列研究。本文分别对两种类型的液晶进行了掺杂,制备了其碳纳米管复合材料,并对其掺杂后的性能进行了研究。(1)通过熔融共混法制备了单变液晶／碳纳米管复合材料,并用偏光显微镜、热重、扫描电镜、拉曼光谱、表面电阻等研究了其掺杂后的性能。从实验结果可以看出,掺杂量很少时,碳纳米管在液晶中可以很好的分散。当掺杂量增大时,由于碳纳米管的自发团聚作用,液晶的指向矢变得混乱,并且碳纳米管束在该液晶相变过程中具有晶核的作用。掺杂碳纳米管后该液晶的电导率有很大的提高,但是热稳定性却降低了。(2)采用高温溶液缩聚法合成了一种热致性液晶聚合物,并利用原位聚合法制备了不同浓度的热致型液晶聚合物／碳纳米管复合材料,通过差示扫描量热法、热重、X-射线衍射、偏光显微镜等研究了其复合物的性能。X-射线衍射说明碳纳米管的加入对液晶聚合物的晶型结构的影响不大。扫描电镜和偏光显微镜说明少量的碳纳米管能够很好的分散在聚合物基体中,而且碳纳米管沿着液晶聚合物的矢量方向很好的排列。热重分析和差示量热扫描结果说明加入少量的碳纳米管能够改善聚合物的热稳定性能,并会提高聚合物的熔融转变温度和各向同性相转变温度。更多还原

【Abstract】 Due to their unique structure, excellent mechanical and photo-electronic properties, carbon nanotubes (CNTs) have been envisioned as promising fillers for nanocomposites. And so many researchers have done much work on the preparation and the study of the properties. In this paper, we prepared two liquid crystal/carbon nanotubes composites through doping, and characterized them.(1) In present work, the MPPB nanocomposites with various concentration MWNTs were prepared by melt mixing to investigate the effect of MWNT doping, via polarized optical microscopy (POM), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), Raman spectroscopy and surface resistance respectively. From the results, the MWNTs were well dispersed in host matrix at low concentration. The LC director field was influenced by the MWNT aggregates which probably acted as the nucleation centres. The sample presented a highly performance in electrical conductivity, expressed as the decrease in surface resistance. For the nanocomposites, no improvement in thermal stability was seen at the initial state of degradation.(2) We synthesized a TLCP via high-temperature solution polycondensation and prepared various concentrations of TLCP/MWNTs by in situ polymerization. Differential scanning calorimetry (DSC), TGA, X-ray diffraction (XRD) and POM were used to investigate the thermal behavior, crystalline structure and liquid crystalline properties of the pure TLCP and TLCP/MWNTs nanocomposites. SEM images showed that the MWNTs were well separated in the TLCP matrix. The X-ray diffraction results suggested that the addition of MWNTs to TLCP did not significantly change the crystal structure of TLCP matrix. The TGA indicated that a small amount of MWNTs could improve the thermal stability of TLCP domains.更多还原